Today I had a deskside (that's beauty-speak for a company coming to your office to tell you about their new products) with Neutrogena Dermatologics; it's a potent retinol-based skin line that sells on QVC. Which is why you can imagine my surprise when I stepped into Allure's lobby to find Dr. Will Kirby—as in Dr. Will the winner (and villain) of 2001's Big Brother. Turns out, he's evolved a bit since his "bros before hos" days on reality TV. Not only is he a totally legit dermatologist with offices in Beverly Hills and Encino, California, he is the leading authority on laser tattoo removal, according to the Skin & Aging journal (who knew??!?). He also happens to know a thing or two about retinol, the tried-and-true wrinkle-reducer. Here's what I learned:

· Traditional retinols are broken down by sunlight, __which is why dermatologists usually recommend them for night use. Neutrogena Dermatologics has a stabilized form of retinol, which Kirby says is fine for day use when paired with sunscreen. (Unfortunately, there's no way to know if a retinol is "stabilized" from the ingredients panel.)

· It can take 57 days of using retinol before you see a difference in your skin, so you've got to be consistent. Kirby says one of the biggest problems with retinol is compliance—which means that people stop using it before it has time to work its magic.

· We often hear that, because retinol can be irritating, you should start out by using it every other or every third day. But that's not ideal, Kirby says. "In a perfect world, you would apply it once an hour," he told me. Since that's not gonna happen, Kirby recommends using a lower dose of retinol, every single day. (You can do this by diluting your favorite product with a plain cream like Cetaphil.) Why? Because retinol exfoliates the surface layer of skin—and then gets to work building collagen below. Waiting too long between doses lets your surface layer build up again, Kirby says, kind of a one-step-forward-two-steps-back thing. And don't take long breaks from the stuff: "If you take a month off of retinol, it's like you're starting over," he says. (In May, Neutrogena Dermatologics is coming out with a Progression Kit, which has three creams with varying levels of retinol, meant to help you ease into it without irritation.)

· Only use a pearl-size amount—it's enough to cover the face, Kirby says. OD'ing on retinol is one reason it causes reactions in so many people's skin. If even a pearl-size dab makes your skin burn or turn red, mix it with a basic moisturizer first, he suggests.